Effect of laser power density on self-generated magnetic field and electron thermal conduction

In order to understand the generation mechanism of self-generated magnetic field and electron thermal conduction characteristics in the process of the interaction between ultra-intense laser and plasma,the strength and spatial distribution of the self-generated magnetic field under different laser power density were estimated by means of electromagnetic relativistic particle-in cell program simulation.The electron-thermal evolvement phenomenon was observed as described by the Spitzer-Harm theory.It is shown that different from previous models,the initial non-Maxwell distributed plasma stimulates the electromagnetic instability in the plasma because of the random thermal motion of electrons.It is not the strong magnetic field excited by instability makes the electron beam deposit the energy within very short distance.Meanwhile,it restrains the electron thermo current to be formed when the laser ponderomotive force bursts through the electron.This result is helpful to the self-magnetic field generation and electron thermal conduction in fast ignition of inertial confinement fusion.